Brazilian UGA Engine differences

The Brazilian Bay 1600cc Dual Port UGA model engine differs from the Standard 1600cc Dual Port engine fitted to "German built" used on Bay window & late beetles.

The main difference is around the Fuel / Air mixture as the Brazilian engine uses a ECU fuel injection system instead of the carburetors.

There are a few more subtle differences which this post aims to highlight.

This is a guide will be useful to anyone who is replacing a UGA code engine to AD code engine.

Crankcase

• The crankcase is a Dual relief case with UGA code stamp. It appears to be similar to a standard AS41 crankcase
• No Bus mounting points on the rear as the Brazilian bay does not use a mounting bar.
• M10 x 1.0mm threaded tapped hole (lower right hand corner) of sump for fitting the Coolant (Oil) Temperature Sensor (CTS)

Cooling Tinware

The main differences around the Tinware are the obvious size and shape of the fan housing with its lack of air heater outlets and overall shape. The rear of the fan housing and oil cooler is very different in design. 

• Dog house fan housing no air heater outlet pipes
• Dog house oil cooler housing smaller and all built in
• Dog house cooling exits fan housing via a circular pipe (with rubber coupling)
• Dog house cooling exits via a circular pipe in front tinware
• Oil cooler is a smaller single port (1200cc) design
• Oil cooler mounts to crankcase via a different adapter than the DP larger version.
• Lower cooling - Cool tins fitted underneath cylinders.
• Lower cooling - No rear deflectors on left and right cylinders
• Lower cooling - No thermostat or flaps are used.
• Lower cooling - The lower sledge shaped cooling scoops are not made of metal. Plastic form covered in aluminium foil on outside and some form of fabric material
• Rear cooling - The tinware which seals against the rear valance is beetle shaped with no air heater cutouts and no breather cutout.

Alternator

• The alternator is a standard Bosch 55A.
• The Alternator stand is different design. It has a round base and O-Ring to seal instead of a square gasket to seal against crankcase.
• The Oil deflection plate is in the stand and is made of black plastic.
• The Alternator clamp is two parts which clamp to the sides of the stand, like two fingers which hook under the stand. Very different to the large round jubliee clamp.
• Alternator is fitted with a finned bladed pulley wheel for cooling.
• Crankcase breather is part of the oil filler neck through a Positive Crankcase Valve (PCV) which circulates back to intake air system just above the throttle body intake.

Fuel Pump

• There is no mechanical fuel pump. The fuel pump is fitted to the fuel tank top side under and inspection plate above.
• The hole and a single gasket fitted to the crankcase
• The gasket and hole are covered by the Inlet manifold mounting bracket.

Intake Manifold

• The intake manifold is a twin pipe construction with a central plenum under the throttle body
• The twin pipes go to twin pipes on the cylinder head manifolds
• There is a twin dual boots to connect the inlet manifold with the cylinder manifolds.
• The manifold boots are the same as a Mexican beetle and do not use any jubliee clamps.
• The inlet manifold has ports for Throttle Body, Brake servo, Evap, Manifold pressure sensor and fuel pressure regulator
• All ports except the servo are push on barbed ports. The servo uses a quick release push fit, the same as the fuel lines in rigid hoses.

Ignition

• Hall effect distributor (no points just a electronic sensor for position 1)
• Standard rotor arm and distributor cap & HT leads.
• No advance mechanism (ECU does all advance timing)
• Square mounted coil on fan housing. Uses ECU signal for triggering coil
• Coil has three pin connections

Air Filter

• Cylinder shaped air filter mounted in drum housing mounted on upper left hand engine bay roof.
• Air from filter comes down a large rubber pipework onto top of Throttle body, secured with a jubliee clip
• Idle Stabilization Valve (ISV) take air from pipe to bypass the throttle body for idling.
• PSV pipework connects to air inlet.
• A center mounted throttle body which has a butterfly valve connecting to the accelerator cable.
• Throttle Position Sensor (TPS) mounted to right hand side of throttle body measures accelerate position.
• Air Temperature Sensor (ATS) is mounted at the front of throttle body
•  Idle stabilization valve (ISV)mounted behind the throttle body for controlling idle.
• Manifold Absolute Pressure sensor (MAP) connects to lower manifold to measure manifold pressure. The MAP is mounted to the right next to ECU above battery.

Fuel System

• Fuel pump is located within the petrol tank
• Pump pressurizes the fuel system to 3 Bar or 2.5 Bar at idle
• Fuel is pump from pump to fuel filter mounted on left side of engine
• The output of the filter goes to the left hand fuel rail then onto the right hand fuel rail via a pipe at the front of the engine bay.
• The left fuel rail outlet goes to a Fuel Pressure regulator (FPR) and is mounted on the right hand of the fan housing
• Mounted on the fuel rails are 4 Bosch EV6 injectors. One injector per cylinder.
• Injectors pulse width is controlled by ECU.
• Bosch Injectors EV6 have narrow spray pattern of 5 Degrees (Stream) design.
• The stream pattern is fired directly into the manifolds onto the inlet valves and into the air flow. 
• The FPR connects to the inlet manifold vacuum so when idling the fuel is returned back to the tank at a pressure of 2.5Bar
• As rpm increases the Vacuum reduces and fuel pressure is regulated to 3 Bar.
• The fuel system uses speed fit push fit connectors and high pressure hoses. The locking clips are internal locking type (no the external type which you use special pliers)

ECU

• The Brazilian engine use a Bosch MP9 Monotronic ECU
• The ECU controls all engine functions especially Fuel mixture ratio, Timing etc.
• VAG COM (VCDS) diagnostics is available via an ODBII connector mounted in front of ECU above the battery on the top right hand side of the engine bay.

Exhaust

• No heat exchangers are used. J-Tube with a flange mounting are located under the left and right cylinder heads.
• Lambda sensor mounted at collector exhaust manifold before catalytic converter
• Manifold connects to a catalytic converter
• Catalytic converter connects to two silencer boxes on the left and right sides before exiting the van n the right hand side. 

Hope information is useful.

Next post is related to the changes you will require when replacing your UGA Brazilian engine with a AD German engine.

Running Rich - Replacement ECU - Solved!

Running Rich - Solved!

Background

For those that have been following this blog for the last 2 years my Brazilian Kombi has been struggling to get through the yearly MOT.

The issue has always been High CO emissions coming at idle and also at fast RPMs.

After investigating the Lambda sensor is always running at about a constant 0.9v which indicates rich levels. The Lambda sensor should run rich / lean (0.1 to 0.9v) averaging out at about stoichiometric of 0.45v (Lambda=1)

I have checked every sensor and actuator and ran many diagnostic logs all without finding anything wrong. 

I finally concluded that the ECU system was not responding to the rich levels and not adjusting. If you inject more fuel (Propane) or ristrict air the ECU should detect this and adjust its fuel (trim) to aim for 0.45v stoichiometric.

At this level the CO emissions should be at the lowest levels.

My original ECU showed NO SIGNS of attempting to correct anything.

So I have now secured another (used) ECU...... It has travelled a 6800 Mile journey to my Kombi (contact me if you need supplier details)

It an earlier version of the original ECU but its basically the same version.

The Swap

The swap over took half a day. Removal of the old ECU was simple enough (battery & wiring disconnecting and one nut)

I then spent a few hours checking all the 25 connections from the ECU ensuring that each Pin went to the correct place compared to the wiring diagram and that all sensors and actuators where correct.

Then came the replacement ECU which was a simple plug in and secure and then reconnecting the battery.

First Start

Then came the moment of truth. First turn of the key the engine fired up first time and sat at Idle with only a little hunting.

After a few minutes everything settled down. Struggled to restart a 2nd time for unknown reason but after that it was fine.

Hooked up the VCDS Diagnostics (see Diagnostics Guide page on the right) and cleared some old fault codes.

Everything ran fine and the drive was improved. A few fault codes came up about Fuel trims but I assume that this was the ECU "Learning" the engine set-up.

The Results

So after a few longer drives I captured some log files and this is the result:

You can now see the Lambda response switching lean / rich during running.

Also of note is the Fuel Injectors switching basically off during letting off the throttle.This is what I would expect to see from a fully working ECU.

During long periods of idle the injectors period are low and the engine is running rich to lean consistently

RESULT!

Follow Up.

Now I have a functioning spare ECU to use on the bus I can now turn my thought to the orginal ECU. I have been starting an ECU repair manual detailing as much little information on the Bosch Motronic MP9 used on the air-cooled Kombi.

I have been speaking to a ECU repair company and will plan to send of the ECU to them to see what they can find.

I suspect from the repair information I suspect it could be an issue with the supply ground of the Sensor inputs not connecting or floating so it does record the right values BUT not be able to respond. Will keep you all updated on the repair.

I suspect the ECU was always faulty and even more damaged when the Engine Earth lead was found disconnected (see hot start issue)

I am SO happy to have finally resolved the issue. I always suspected it was the engine, timing or sensor wiring issue BUT never suspected the ECU to be at fault. 

I did not want to be a typical parts swapper mechanic condemning ECUs but in this case it was the ECU!

More details and information to follow!

*** NEW *** Diagnostics Manual Now online

The NEW Diagnostics Manual is now on-line!

See the link in the pages section on the right

OR click the link here

http://t2bay.blogspot.co.uk/p/blog-page.html

Its a very early draft and is to help out some the Brazilian Air-Cooled owners to resolve some issues.

Please contact me if you need any help or more information.

As always I do this for FREE so please, please click the donate button if you use this and wish to support me further.

Still Running Rich?

So I have gone back through diagnostic log files from over 2 years now in order to work out why my engine is running rich (Failed emissions and also poor fuel economy) and also black exhaust.

Following graphs taken at different date intervals

RPM, Lambda Regulation, Engine load and injector pulse widths

06/07/14 - Runs at around 0.8-0.9 except when de-accelerating. Still looks like its running rich but plenty of lean.

14/10/14 - Runs at around 0.8-0.9 except when de-accelerating. Still looking rich but again some lean.

05/08/15 - After fitting in March new "universal" sensor. Not really sure what's going on could be "normal" but no real regulation.

12/12/15 - Lambda Runs most of the time at 0.45v. Signal very poor stuck around 0.45v little response.

At this time the "universal" sensor response was stuck at 0.45v confirmed by unplugging and it stays at 0.45v

Decided to fit OEM Bosch Sesnor.

20/12/15 - Fitted new Lambda Sensor. Improved over previous BUT only a very few lean points.

UPDATE:

Changed FPR regulator after issues seen with Fuel Pressure tests. Re run the same trip:

No to confirm the lambda signal I removed it. Fixed it out of the way. Rerun the same drive. Very noisy from the hole left behind.

From the above graphs 2014 was before last MOT and engine seems to be have high Lambda except during de-acceleration

2015 March (03) time fitted "universal" lambda sensor due to emissions failure. at some point from then on sensor started to run constantly 0.45v

Fitting the OEM Bosch sensor on 20/12/15 the sensor has started to indicate rich at around 0.8 / 0.9v similar to 2014 at the later parts of the graph but still with not much rich / lean switching going on here.

SO in summary:

At the first traces some rich / lean cycling fitting universal sensor failed within 6-8 months.

Fitting OEM Bosch sensor improves response BUT still looking rich with little rich / lean.

I have then proceeded in using my USB oscilloscope to check the actual sensor response.

As you can see it is actually rich at 0.8v. Blipped the throttle a few times and saw the response drop from rich / lean BUT not switching enough only on de-accelerating.

So in conclusion:

Diagnostics logs & Scope of OEM sensor show rich.
Unsure if ECU actually switches rich / lean in response to o2

Things to yet to confirm / check:

1. Fuel Pressure Test - Too much fuel-Fuel Pressure regulator / Stuck Injectors - Completed - Fuel pressure decay at full vacuum - Replaced FPR - No difference. Still could be injectors. Repeat tests with FPR.
2. All Cylinders firing - One not firing - Incomplete fuel burnt
3. Find more info on ECU - Does it switch (need another Kombi / Info) - Looks like artificial lean (removed) makes no difference to Injection on time. I am suspecting that this MP9 ECU does not operate a closed loop so the Lambda is just for indication or base level of injection timing.
4. Lambda Sensor - New OEM sensor works fine out of exhaust (Lean) and Rich when in exhaust.
5. Blocked Exhaust - Still could be block CAT or exhaust - Plan is remove the CAT with Lambda in place and check signal. Inspect CAT.
6. TPS - Maybe TPS showing 6.7 degrees at Idle is causing the lack of lean at idle due to the ECU still thinking its open (foot on throttle) - Will need to reset the TPS by checking that Butterfly is actually closed and ECU detects no throttle.